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806 head inferiority ?

This is a discussion on 806 head inferiority ? within the Internal Engine forums, part of the LSx Technical Help Section category; Looking for input on the early `98 806 Heads There was a discussion on another Forum and some claim that ...

  1. #1
    Firebird Encyclopedia 9T8W66's Avatar
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    806 head inferiority ?

    Looking for input on the early `98 806 Heads
    There was a discussion on another Forum and some claim that they are inferior to 853 and 241 castings. My question is IF they are inferior what is the differnce going to be ? If it's less than 10 HP difference between them and the later heads To Me thats not enough to call them inferior. I mean you wouldn't necessarily feel that on the street. 10 HP and above you may notice but not less than 10 HP.
    I'm looking for substantial Proof, Not hearsay
    thanks for any responses.
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    Member 98ls1blackbird's Avatar
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    I'm not knocking 806 heads, but if you look at the stock flow numbers of the 806 heads versus the later model 241 heads, they do flow quite a lot less. I dont have the numbers before me but they are in the book LS1/LS1 performance by Christopher Andres. This should be required reading for anyone wanting to modify an LSx engine, available at most speed shops. If you really want the numbers I can look them up.
    I have a set of SLP CNC ported 806 castings that I will be putting on in the spring when the TA comes out of storage. I'll know then if they make much more power after I get it dynoed. I went with the 806 heads so I didnt have to mess around with new valve covers and coil mount brackets. I dont know if this helps much, but I dont have any real hard data.
    I have heard that one reason the 806 heads did not flow as well as later heads is the exhaust manifolds were a lot more restrictive. LT headers should solve that problem. Good luck.

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    Firebird Encyclopedia 9T8W66's Avatar
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    Thanks for the response
    I have that book and your correct it does list flow numbers but it is for all LS1 heads in general not specifically 806's and it doesn't list 806's vs 853/241's
    It does list 243's (LS6 heads) against LS1 heads but thats it.
    I can't see them changing the casting that much to show a noticeable gain.
    The exhaust manifiold restriction makes sense to me though. I know the castiron manifolds from `00 up do flow better.

    Again thanks for the response.

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    Member 98ls1blackbird's Avatar
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    Sorry man, I thought it listed the numbers for the 806 heads, but it has been awhile since I read through it. Good luck with your choice. Where in Mi. are you from? I'm in Grand Rapids area, Jenison.

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    I'm not buying anything in the near future I have 806's on my car and was just curious if there was a substantial difference.
    Good talkin to ya.

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    As far as I know they only real difference in the casting is the fact that it went from perimeter bolt valve covers to center bolt. Perimeter bolt is said to be weaker than center bolt HOWEVER most people wont make the power to be able to break either head casting. I have a 99 and bought a set of 98 port and polished CNCed heads because I got a good deal on them.

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    Quote Originally Posted by juiced99ws6 View Post
    As far as I know they only real difference in the casting is the fact that it went from perimeter bolt valve covers to center bolt. Perimeter bolt is said to be weaker than center bolt HOWEVER most people wont make the power to be able to break either head casting. I have a 99 and bought a set of 98 port and polished CNCed heads because I got a good deal on them.

    Ya That's what I thought also but someone on LS1Tech said the intake ports on later heads were machined slightly vs the early heads which were left as cast. I never paid that much attention and I've never had my intake off so I can't say if it is true or not. Regardless I think it is all hearsay and a ploy to sell ported heads.

    I was never looking into buying heads anyway I would much rather just Cam it and get the most out of it that way. Most Cam and bolt on cars are in the 375-385 HP range, and I would be happy with that.

    Of corse I'm at 113K and if the motor goes I'll cam an LS2 and slap that in there.

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    Member 98ls1blackbird's Avatar
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    Quote Originally Posted by 9T8W66 View Post
    Ya That's what I thought also but someone on LS1Tech said the intake ports on later heads were machined slightly vs the early heads which were left as cast. I never paid that much attention and I've never had my intake off so I can't say if it is true or not. Regardless I think it is all hearsay and a ploy to sell ported heads.

    I was never looking into buying heads anyway I would much rather just Cam it and get the most out of it that way. Most Cam and bolt on cars are in the 375-385 HP range, and I would be happy with that.

    Of corse I'm at 113K and if the motor goes I'll cam an LS2 and slap that in there.
    Amen to that. I'm at 102k and if it goes, LS2.

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